One of the early adopters of the configure-ovs alternative feature (which I'm proposing to rename "custom br-ex") is using UPI and wants to do the initial bridge configuration via kernel args instead of NMState. In preliminary testing this is working well for them and I think it's a reasonable use case. It does introduce some additional risk since writing a valid day 2 configuration will be harder without a day 1 config to start with, but since Kubernetes-NMState should roll back any completely invalid configurations I think it's worth the risk.